gh-157056: Add tests and NEWS for STRING format comprehension annotations

Author: KingLizard1020

Lib/test/test_annotationlib_string_special.py

@@ -0,0 +1,57 @@
+"""STRING-format edge cases for annotationlib (gh-157056)."""
+
+import unittest
+
+from annotationlib import Format, get_annotations, type_repr
+
+
+class TestStringFormatSpecialAnnotations(unittest.TestCase):
+    def test_dict_comprehension_annotation(self):
+        def f(x: {k: v for k, v in items}):
+            pass
+
+        self.assertEqual(
+            get_annotations(f, format=Format.STRING),
+            {"x": "{k: v for k, v in items}"},
+        )
+
+    def test_lambda_annotation(self):
+        def g(x: lambda q: q):
+            pass
+
+        g_anno = get_annotations(g, format=Format.STRING)
+        self.assertEqual(g_anno, {"x": "lambda q: q"})
+        self.assertNotIn("0x", g_anno["x"].lower())
+
+    def test_generator_expression_annotation(self):
+        def h(x: (w for w in seq)):
+            pass
+
+        h_anno = get_annotations(h, format=Format.STRING)
+        self.assertEqual(h_anno, {"x": "(w for w in seq)"})
+        self.assertNotIn("0x", h_anno["x"].lower())
+
+    def test_mixed_annotations(self):
+        def mixed(a: int, b: {k: v for k, v in items}, c: lambda q: q):
+            pass
+
+        self.assertEqual(
+            get_annotations(mixed, format=Format.STRING),
+            {
+                "a": "int",
+                "b": "{k: v for k, v in items}",
+                "c": "lambda q: q",
+            },
+        )
+
+    def test_type_repr_lambda_and_genexpr_have_no_address(self):
+        lam = lambda q: q
+        self.assertTrue(type_repr(lam).endswith("<lambda>"))
+        self.assertNotIn("0x", type_repr(lam).lower())
+        gen = (w for w in ())
+        self.assertTrue(type_repr(gen).endswith("<genexpr>"))
+        self.assertNotIn("0x", type_repr(gen).lower())
+
+
+if __name__ == "__main__":
+    unittest.main()

Misc/NEWS.d/next/Library/2026-09-08-01-00-00.gh-issue-157056.annotstr.rst

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+:func:`annotationlib.get_annotations` with ``format=Format.STRING`` no
+longer fails on dict-comprehension annotations, and no longer emits
+non-deterministic strings that embed a memory address for ``lambda`` and
+generator-expression annotations.